1. Field of the Invention
The present invention relates to a hydromechanical transmission shifting control system. More particularly, the present invention relates to a hydromechanical transmission shifting control system having a variable displacement component of a hydrostatic unit and a set of clutches which are controlled by a microcontroller which senses various conditions.
2. Problems in the Art
Hydromechanical transmission control systems are known in the art. A hydromechanical transmission has the ability to have a continuously variable ratio coverage over a wide torque and speed range. As a result, vehicle operating characteristics at the output or at the engine can be improved. For example, a transmission control system can be used to obtain maximum power for acceleration, optimum fuel economy, or a fixed output speed control. Typically, prior transmission control systems use a number of hydraulic logic valves to accomplish the control requirements. While these systems are able to control the hydromechanical transmission, they have disadvantages including inflexibility, high cost, complexity, etc.